The present invention relates to a process for producing hydroxybenzenes such as resorcinol from (a) .alpha., .alpha.-di-alkyl-.alpha.-hydroxymethyl group containing benzenes such as m-diisopropylbenzenedicarbinol and/or (b) benzenes containing both .alpha., .alpha.-dialkyl-.alpha.-hydroxymethyl and .alpha., .alpha.-dialkyl-.alpha.-hydroperoxymethyl groups, such as m-diisopropylbenzenemonocarbinol monohydro-peroxide.
A well known method for producing hydroxybenzenes such as resorcinol consists of oxidizing m-diisopropylbenzene (m-DIPB) with molecular oxygen in the presence of a base to obtain m-diisopropylbenzene dihydroperoxide (m-DHP), then decomposing m-DHP with an acid to yield resorcinol. Besides m-DHP, this method gives rise to by-product carbinols such as m-diisopropylbenzenemonocarbinol monohydroperoxide (m-HHP) and m-diisopropylbenzenedicarbinol(m-DC). Therefore, for commercial processes of resorcinol production by oxidation of m-DIPB followed by decomposition of m-DHP with an acid, it has been proposed that the by-product carbinols be reoxidized with hydrogen peroxide to form m-DHP, which may then be decomposed into resorcinol with an acid (see, for example, Japanese Patent Publication No. 52972/1983).
In this prior art process, a mixture of oxidation products containing carbinols in addition to the hydroperoxide obtained by oxidizing m-DIPB with molecular oxygen is first oxidized with hydrogen peroxide in the presence of an acid such as sulfuric acid and an aromatic hydrocarbon solvent such as toluene or a ketone solvent such as methyl isobutyl ketone, thereby reoxidizing the carbinols to form concentrated m-DHP, and in the next step, the m-DHP of increased concentration is decomposed into resorcinol with an acid. This prior art process depends on a two-stage reaction since it is difficult to achieve both reoxidation with hydrogen peroxide and decomposition with an acid simultaneously in a single step. Moreover, the two-stage reaction involves complicated procedures and results in a costly process. In addition, the yield of resorcinol produced by this method is not necessarily high.
Japanese Patent Application (OPI) No. 282333/1986 (the term "OPI" as used herein means an unexamined published Japanese patent application) discloses a one-step process for the production of 2, 6-dihydroxynaphthalene (2, 6-DHN) in which 2, 6-diisopropylnaphthalene dicarbinol is oxidized with hydrogen peroxide and acid-decomposed in acetonitrile or dioxane in the presence of an inorganic acid. Japanese Patent Applicatin No. 209275/1985 also shows a process for 2, 6-DHN production and teaches that if a solution of the oxidation product of 2, 6-diisopropylnaphthalene (2, 6-DIPN) dissolved in ketone or toluene is subjected to oxidation and decomposition with H.sub.2 O.sub.2 in the presence of an acid, 2, 6-DHN can be obtained in high yield by a one-step reaction without using two-stage reaction. The process disclosed in Japanese Patent Application (OPI) No. 282333/1986 shows that a satisfactory yield of 2, 6-DHN can be produced from the pure dicarbinol of 2, 6-DIPN even if the reaction is carried out in acetonitrile or dioxane. Therefore, these two processes, notwithstanding the difference in the starting material employed (dicarbinol of 2, 6-DIPN in one method and the oxidation product of 2, 6-DIPN in the other), are both directed to the production of 2, 6-DHN using H.sub.2 O.sub.2 as an oxidizer and attain their objective by an efficient one-stage reaction performed in a solvent such as ketone, aromatic hydrocarbon, acetonitrile or dioxane.
However, the starting material for the process described in Japanese Patent Application (OPI) No. 282333/1986 has a naphthalene nucleus and it is not clear whether the process can also be applied to starting materials having a benzene nucleus. The starting material to be subjected to the reaction involved in that process is a pure form of dicarbinol containing no impurities. As already pointed out, if polyalkylbenzenes such as m-diisopropylbenzene are oxidized with molecular oxygen, a variety of oxides such as dihydroperoxide, monocarbinol monohydroperoxide and dicarbinol are produced in the form of mixtures. But it is unclear whether the process disclosed in Japanese Patent Appplication (OPI) No. 282333/1986 is equally applicable to mixtures of oxidation products that contain hydroperoxides in addition to carbinol.